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Search Results: 1 - 10 of 494374 matches for " Valence M. K. Ndesendo "
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Molecular Docking and ADMET Study of Emodin Derivatives as Anticancer Inhibitors of NAT2, COX2 and TOP1 Enzymes  [PDF]
Daniel M. Shadrack, Valence M. K. Ndesendo
Computational Molecular Bioscience (CMB) , 2017, DOI: 10.4236/cmb.2017.71001
Abstract: Over the past years natural products and/or their derivatives have continued to provide cancer chemotherapeutics. Glycosides derivatives of emodin are known to possess anticancer activities. An in silico study was carried out to evaluate emodin derivatives as inhibitors of Arylamine N-Acetyltransferase 2, Cyclooxygenase 2 and Topoisomerase 1 enzymes, predict their pharmacokinetics and explore their bonding modes. Molecular docking study suggested that D2, D5, D6 and D9 to be potent inhibitors of NAT2, while D8 was suggested to be a potent inhibitor of TOP1. Derivatives D2, D5, D6 and D9 bind to the same pocket with different binding conformation. Pharmacokinetic study suggested that selected emodin derivatives can be potential cancer chemotherapeutic agent. Physicochemical parameters such density, balaban index, surface tension, logP and molar reflectance correlated to compounds activity. These finding provides a potential strategy towards developing NAT2 and TOP1 inhibitors.
A Review on Composite Liposomal Technologies for Specialized Drug Delivery
Maluta S. Mufamadi,Viness Pillay,Yahya E. Choonara,Lisa C. Du Toit,Girish Modi,Dinesh Naidoo,Valence M. K. Ndesendo
Journal of Drug Delivery , 2011, DOI: 10.1155/2011/939851
Abstract: The combination of liposomes with polymeric scaffolds could revolutionize the current state of drug delivery technology. Although liposomes have been extensively studied as a promising drug delivery model for bioactive compounds, there still remain major drawbacks for widespread pharmaceutical application. Two approaches for overcoming the factors related to the suboptimal efficacy of liposomes in drug delivery have been suggested. The first entails modifying the liposome surface with functional moieties, while the second involves integration of pre-encapsulated drug-loaded liposomes within depot polymeric scaffolds. This attempts to provide ingenious solutions to the limitations of conventional liposomes such as short plasma half-lives, toxicity, stability, and poor control of drug release over prolonged periods. This review delineates the key advances in composite technologies that merge the concepts of depot polymeric scaffolds with liposome technology to overcome the limitations of conventional liposomes for pharmaceutical applications.
Composite Polylactic-Methacrylic Acid Copolymer Nanoparticles for the Delivery of Methotrexate
Bongani Sibeko,Yahya E. Choonara,Lisa C. du Toit,Girish Modi,Dinesh Naidoo,Riaz A. Khan,Pradeep Kumar,Valence M. K. Ndesendo,Sunny E. Iyuke,Viness Pillay
Journal of Drug Delivery , 2012, DOI: 10.1155/2012/579629
Abstract: The purpose of this study was to develop poly(lactic acid)-methacrylic acid copolymeric nanoparticles with the potential to serve as nanocarrier systems for methotrexate (MTX) used in the chemotherapy of primary central nervous system lymphoma (PCNSL). Nanoparticles were prepared by a double emulsion solvent evaporation technique employing a 3-Factor Box-Behnken experimental design strategy. Analysis of particle size, absolute zeta potential, polydispersity (Pdl), morphology, drug-loading capacity (DLC), structural transitions through FTIR spectroscopy, and drug release kinetics was undertaken. Molecular modelling elucidated the mechanisms of the experimental findings. Nanoparticles with particle sizes ranging from 211.0 to 378.3 nm and a recovery range of 36.8–86.2 mg (Pdl≤0.5) were synthesized. DLC values were initially low (12±0.5%) but were finally optimized to 98±0.3%. FTIR studies elucidated the comixing of MTX within the nanoparticles. An initial burst release (50% of MTX released in 24 hours) was obtained which was followed by a prolonged release phase of MTX over 84 hours. SEM images revealed near-spherical nanoparticles, while TEM micrographs revealed the presence of MTX within the nanoparticles. Stable nanoparticles were formed as corroborated by the chemometric modelling studies undertaken.
Trends in the Molecular Pathogenesis and Clinical Therapeutics of Common Neurodegenerative Disorders
Yahya E. Choonara,Viness Pillay,Lisa C. Du Toit,Girish Modi,Dinesh Naidoo,Valence M.K. Ndesendo,Sibongile R. Sibambo
International Journal of Molecular Sciences , 2009, DOI: 10.3390/ijms10062510
Abstract: The term neurodegenerative disorders, encompasses a variety of underlying conditions, sporadic and/or familial and are characterized by the persistent loss of neuronal subtypes. These disorders can disrupt molecular pathways, synapses, neuronal subpopulations and local circuits in specific brain regions, as well as higher-order neural networks. Abnormal network activities may result in a vicious cycle, further impairing the integrity and functions of neurons and synapses, for example, through aberrant excitation or inhibition. The most common neurodegenerative disorders are Alzheimer’s disease, Parkinson’s disease, Amyotrophic Lateral Sclerosis and Huntington’s disease. The molecular features of these disorders have been extensively researched and various unique neurotherapeutic interventions have been developed. However, there is an enormous coercion to integrate the existing knowledge in order to intensify the reliability with which neurodegenerative disorders can be diagnosed and treated. The objective of this review article is therefore to assimilate these disorders’ in terms of their neuropathology, neurogenetics, etiology, trends in pharmacological treatment, clinical management, and the use of innovative neurotherapeutic interventions.
Oral Drug Delivery Systems Comprising Altered Geometric Configurations for Controlled Drug Delivery
Kovanya Moodley,Viness Pillay,Yahya E. Choonara,Lisa C. du Toit,Valence M. K. Ndesendo,Pradeep Kumar,Shivaan Cooppan,Priya Bawa
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13010018
Abstract: Recent pharmaceutical research has focused on controlled drug delivery having an advantage over conventional methods. Adequate controlled plasma drug levels, reduced side effects as well as improved patient compliance are some of the benefits that these systems may offer. Controlled delivery systems that can provide zero-order drug delivery have the potential for maximizing efficacy while minimizing dose frequency and toxicity. Thus, zero-order drug release is ideal in a large area of drug delivery which has therefore led to the development of various technologies with such drug release patterns. Systems such as multilayered tablets and other geometrically altered devices have been created to perform this function. One of the principles of multilayered tablets involves creating a constant surface area for release. Polymeric materials play an important role in the functioning of these systems. Technologies developed to date include among others: Geomatrix ? multilayered tablets, which utilizes specific polymers that may act as barriers to control drug release; Procise ?, which has a core with an aperture that can be modified to achieve various types of drug release; core-in-cup tablets, where the core matrix is coated on one surface while the circumference forms a cup around it; donut-shaped devices, which possess a centrally-placed aperture hole and Dome Matrix ? as well as “release modules assemblage”, which can offer alternating drug release patterns. This review discusses the novel altered geometric system technologies that have been developed to provide controlled drug release, also focusing on polymers that have been employed in such developments.
Fabrication, Modeling and Characterization of?Multi-Crosslinked Methacrylate Copolymeric?Nanoparticles for Oral Drug Delivery
Ndidi C. Ngwuluka,Viness Pillay,Yahya E. Choonara,Girish Modi,Dinesh Naidoo,Lisa C. du Toit,Pradeep Kumar,Valence M.K. Ndesendo,Riaz A. Khan
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12096194
Abstract: Nanotechnology remains the field to explore in the quest to enhance therapeutic efficacies of existing drugs. Fabrication of a methacrylate copolymer-lipid nanoparticulate (MCN) system was explored in this study for oral drug delivery of levodopa. The nanoparticles were fabricated employing multicrosslinking technology and characterized for particle size, zeta potential, morphology, structural modification, drug entrapment efficiency and in vitro drug release. Chemometric Computational (CC) modeling was conducted to deduce the mechanism of nanoparticle synthesis as well as to corroborate the experimental findings. The CC modeling deduced that the nanoparticles synthesis may have followed the mixed triangular formations or the mixed patterns. They were found to be hollow nanocapsules with a size ranging from 152 nm (methacrylate copolymer) to 321 nm (methacrylate copolymer blend) and a zeta potential range of 15.8–43.3 mV. The nanoparticles were directly compressible and it was found that the desired rate of drug release could be achieved by formulating the nanoparticles as a nanosuspension, and then directly compressing them into tablet matrices or incorporating the nanoparticles directly into polymer tablet matrices. However, sustained release of MCNs was achieved only when it was incorporated into a polymer matrix. The experimental results were well corroborated by the CC modeling. The developed technology may be potentially useful for the fabrication of multi-crosslinked polymer blend nanoparticles for oral drug delivery.
Integration of Biosensors and Drug Delivery Technologies for Early Detection and Chronic Management of Illness
Mpho Ngoepe,Yahya E. Choonara,Charu Tyagi,Lomas Kumar Tomar,Lisa C. du Toit,Pradeep Kumar,Valence M. K. Ndesendo,Viness Pillay
Sensors , 2013, DOI: 10.3390/s130607680
Abstract: Recent advances in biosensor design and sensing efficacy need to be amalgamated with research in responsive drug delivery systems for building superior health or illness regimes and ensuring good patient compliance. A variety of illnesses require continuous monitoring in order to have efficient illness intervention. Physicochemical changes in the body can signify the occurrence of an illness before it manifests. Even with the usage of sensors that allow diagnosis and prognosis of the illness, medical intervention still has its downfalls. Late detection of illness can reduce the efficacy of therapeutics. Furthermore, the conventional modes of treatment can cause side-effects such as tissue damage (chemotherapy and rhabdomyolysis) and induce other forms of illness (hepatotoxicity). The use of drug delivery systems enables the lowering of side-effects with subsequent improvement in patient compliance. Chronic illnesses require continuous monitoring and medical intervention for efficient treatment to be achieved. Therefore, designing a responsive system that will reciprocate to the physicochemical changes may offer superior therapeutic activity. In this respect, integration of biosensors and drug delivery is a proficient approach and requires designing an implantable system that has a closed loop system. This offers regulation of the changes by means of releasing a therapeutic agent whenever illness biomarkers prevail. Proper selection of biomarkers is vital as this is key for diagnosis and a stimulation factor for responsive drug delivery. By detecting an illness before it manifests by means of biomarkers levels, therapeutic dosing would relate to the severity of such changes. In this review various biosensors and drug delivery systems are discussed in order to assess the challenges and future perspectives of integrating biosensors and drug delivery systems for detection and management of chronic illness.
Apprehending and Preventing Patient Withdrawal From Orthodontic Treatment
Gustin A,Busson O,Tréguier M,De Valence H
Revue Médicale de l'Assurance Maladie , 2003,
Abstract: Aims: To determine the percentage, characteristics and causes of patient withdrawal from orthodontic treatments and to assess the public health and economic stakes involved. Method: We performed a retrospective study based on two patient samples from the general scheme and the agricultural scheme of the French national health fund. In the first sample, we enrolled patients who had obtained prior approval for a first six-month period of orthodontic treatment and in the second sample, we enrolled patients who either had approval or refusal of their request for a fifth six-month period of orthodontic treatment during the months of April or May 1998. Study data was obtained by the funds’ salaried dental-surgeon advisors following the clinical examination and questionnaires submitted to concerned patients and questionnaires addressed to attending dental-surgeons. Results: 2,089 affiliates were examined and 3,916 attending dental- surgeons answered the questionnaires. Nationwide, 16.1% of the patients withdrew from their orthodontic treatment, but there were important differences found according to geographic regions. In nine out of ten cases, the patient withdrew from treatment on his own initiative. When patients withdrew from treatment during the first two years, three reasons were found: treatment constraints, treatment cost and failure to comprehend the consequences of withdrawal from treatment. 68% of the patients who withdrew from treatment had one or a number of residual, pathological dysmorphoses. Conclusion: While the results showed that only a limited percentage of patients withdrew from treatment, the public health implications are far from negligible. As a result, the health funds have undertaken a program to sensitize healthcare professionals by informing them of the study’s findings. In addition, a leaflet will be distributed to affiliates of the health-funds in order to make them aware of the stakes involved in orthodontic treatments and the consequences of early withdrawal.
Innovation, Procurement and Construction Industry Development
Geard de Valence
Australasian Journal of Construction Economics and Building , 2010,
Abstract: The implications for analysis of innovation in construction of theoretical developments in industrial organisation are considered in this research, as an attempt to outline a new approach to construction innovation incorporating the ideas found in knowledge based, technology centred models. The paper firstly summarises characteristics of the construction industry, focusing on their effects on innovation, before surveying some of the ideas about the sources of innovation and the expansion and application of knowledge. Construction can be seen as an industry with limited scope for knowledge externalities, where the procurement methods used by the industry’s clients do not pay for innovation. The following discussion uses recent developments in the research on the economics of innovation and industrial organization theory, such as research intensity and the endogenous sunk costs in competitive, fragmented, low research intensity industries. The effects on R&D of procurement methods and on industry structure are discussed, with a focus on the appropriability of innovations and the role of the client on the Heathrow Terminal 5 project. The paper concludes that the procurement methods used for building and construction projects appears to be a determining factor in the level of innovation in the construction industry
Defining an Industry: What is the Size and Scope of the Australian Building and Construction Industry
Gerard de Valence
Australasian Journal of Construction Economics and Building , 2011,
Abstract: The analysis and understanding of the conduct and performance of an industry begins with a study of its structure. However, before analysing an industry's structure it is necessary to define the industry and identify its size, scope and scale to establish its true economic contribution. This paper discusses the size and scope of the Australian building and construction industry, firstly, from a traditional industry economics approach by firm size and business characteristics using data from three construction industry surveys done over 15 years by the ABS. Secondly, data from an industry 'cluster' perspective is shown. The objective of the paper is to compare the differences found in industry size and scope in the structure-conduct-performance approach and the alternative industry cluster approach. Each model reveals different characteristics of the industry. The conclusion finds that the building and construction industry is a case where the traditional structure-conduct-performance model cannot be easily applied. 53
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